STUDY DESIGN: This will be a randomized, placebo-controlled crossover study where patients will receive an evening dose of either aclidinium/formoterol (ACL/FOR) or placebo after steady-state conditions on twice-daily ACL/FOR have been established. Patients will continue to take the same dosage of inhaled corticosteroid (ICS) as they did prior to study entry. Subjects will complete 4 visits as part of the study, with a fifth follow-up visit if required to ensure return to pre-study health status. After an initial screening visit (Visit 1) to confirm eligibility and a 1-week run-in period on stable triple therapy \[long-acting beta2-agonist/inhaled corticosteroid (LABA/ICS) + long-acting muscarinic antagonist (LAMA)\], subjects will complete baseline testing (Visit 2) which includes: full pulmonary function tests, sleep/symptom questionnaires, and polysomnography which will include periodic measurements of overnight spirometry (sitting and supine). Subjects will then receive 2-week treatment with twice-daily ACL/FOR and continue on the same ICS as during the baseline run-in. Once stability on treatment with ACL/FOR and ICS is established, there will be two overnight treatment visits (Visits 3 and 4), conducted 3-7 days apart to allow for return to normal sleep status between. For these visits, the evening dose of ACL/FOR versus placebo will be randomized to treatment order. Treatment visits will be similar to visit 2 but will include overnight measurements of respiratory mechanics (diaphragm electromyography and respiratory pressures). Short-acting bronchodilators will be withheld for at least 8 hours prior to visits.
SAMPLE SIZE: This is an exploratory physiological study with the primary outcome being an improvement in morning pre-dose trough inspiratory capacity (IC) by 200 ml. A sample size of 20 will provide at least 80% to detect this treatment difference based on a standard deviation (SD) of approximately 0.2 L for a response difference in trough IC (vanNoord, 2006), a two-tailed test and a p\<0.05. The investigators anticipate that all patients will not consent to instrumentation; however, the investigators are hoping for n=12 with respiratory mechanical measurements. Due to the complexity of the study and its measurements, an interim analysis will be conducted after 10 subjects have been completed.
